Sensor device

ABSTRACT

Embodiments of a sensor device and methods for manufacturing the same are disclosed. In one embodiment, a sensor device comprises a piezoelectric micromechanical ultrasonic transducer (PMUT) array configured to transmit and receive ultrasonic signals, where the PMUT array comprises a plurality of PMUTs and the PMUT array is flexible, one or more integrated circuits configured to process the ultrasonic signals, a battery configured to provide power to the PMUT array and the one or more integrated circuits, a coupling material configured to hold the PMUT array, the one or more integrated circuits, and the battery, and a capsule configured to seal the PMUT array, the one or more integrated circuits, the battery and the coupling material within the capsule.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. patent application No.62/302,085, “A Sensor Device,” filed Mar. 1, 2016, which is assigned tothe assignee hereof. The aforementioned United States patent applicationis hereby incorporated by reference in its entirety.

FIELD

The present disclosure relates to the field of ultrasonic sensors. Inparticular, the present disclosure relates to embodiments of a sensordevice and methods for manufacturing the same.

BACKGROUND

Some conventional ultrasonic transducer devices, such as the devicesdescribed in U.S. Pat. No. 5,744,898 and U.S. Pat. No. 8,596,140 B2,tend to be rigid and large in size. These devices are not suited to beadopted as an implantable or ingestible device for non-invasive imagingapplications. In some recently improved ultrasound diagnostic imagingdevices, such as the devices described in U.S. Patent Application2014/0276079 A1, require a tube/wire along with the ultrasoundtransducers to be inserted into a patient. These devices are alsounsuitable to be adopted as an implantable or ingestible device fornon-invasive imaging applications. In some other ultrasonic transducerdevices, such as the devices described in US Patent Application2011/0130658 A1 and U.S. Pat. No. 8,647,328 B2, are concerned with usingthe devices, but fail to address the apparatuses and methods for makingsuch devices small with a plurality of flexible ultrasonic transducers,integrated circuits, battery, and printed circuit board such that thesecomponents may be packaged into a sensor device for implantable oringestible device for non-invasive imaging applications. Therefore,there is a need for apparatuses and methods for manufacturing a sensordevice that may be adopted as an implantable or ingestible device fornon-invasive imaging applications.

SUMMARY

Embodiments of a sensor device and methods for manufacturing the sameare disclosed. In one embodiment, a sensor device comprises apiezoelectric micromechanical ultrasonic transducer (PMUT) arrayconfigured to transmit and receive ultrasonic signals, where the PMUTarray comprises a plurality of PMUTs and the PMUT array is flexible, oneor more integrated circuits configured to process the ultrasonicsignals, a battery configured to provide power to the PMUT array and theone or more integrated circuits, a coupling material configured to holdthe PMUT array, the one or more integrated circuits, and the battery,and a capsule configured to seal the PMUT array, the one or moreintegrated circuits, the battery and the coupling material within thecapsule.

BRIEF DESCRIPTION OF THE DRAWINGS

The aforementioned features and advantages of the disclosure, as well asadditional features and advantages thereof, will be more clearlyunderstandable after reading detailed descriptions of embodiments of thedisclosure in conjunction with the non-limiting and non-exhaustiveaspects of following drawings. The drawings are shown for illustrationpurposes and they are not drawn to scale. Like numbers are usedthroughout the figures.

FIGS. 1A-1B illustrate an embodiment of a sensor device according toaspects of the present disclosure.

FIGS. 2A-2B illustrate another embodiment of a sensor device accordingto aspects of the present disclosure.

FIGS. 3A-3B illustrate yet another embodiment of a sensor deviceaccording to aspects of the present disclosure.

FIGS. 4A-4B illustrate yet another embodiment of a sensor deviceaccording to aspects of the present disclosure.

FIGS. 5A-5B illustrate yet another embodiment of a sensor deviceaccording to aspects of the present disclosure.

FIGS. 6A-6D illustrate exemplary implementations of coupling one or moreintegrated circuits to a PMUT array according to aspects of the presentdisclosure.

FIGS. 7A-7E illustrate exemplary embodiments of PMUT arrays according toaspects of the present disclosure.

FIGS. 8A-8P illustrate an exemplary implementation of forming a flexiblePMUT array for coupling external logic according to aspects of thepresent disclosure.

FIGS. 9A-9M illustrate another exemplary implementation of forming aflexible PMUT array for coupling external logic according to aspects ofthe present disclosure.

FIGS. 10A-10E illustrate a method of manufacturing a sensor deviceaccording to aspects of the present disclosure.

FIGS. 11A-11E illustrate a method of manufacturing a sensor deviceaccording to aspects of the present disclosure.

DESCRIPTION OF EMBODIMENTS

Embodiments of a sensor device and methods for manufacturing the sameare disclosed. The following descriptions are presented to enable anyperson skilled in the art to make and use the disclosure. Descriptionsof specific embodiments and applications are provided only as examples.Various modifications and combinations of the examples described hereinwill be readily apparent to those skilled in the art, and the generalprinciples defined herein may be applied to other examples andapplications without departing from the scope of the disclosure. Thus,the present disclosure is not intended to be limited to the examplesdescribed and shown, but is to be accorded the scope consistent with theprinciples and features disclosed herein. The word “exemplary” or“example” is used herein to mean “serving as an example, instance, orillustration.” Any aspect or embodiment described herein as “exemplary”or as an “example” in not necessarily to be construed as preferred oradvantageous over other aspects or embodiments.

According to aspects of the present disclosure, the sensor devicedescribed herein may be adapted to be an implantable or ingestibledevice for non-invasive detailed imaging using flexible or rigid PMUTarrays. The sensor device may also be adapted to be a part of wearabledevices for monitoring and therapeutic applications. The sensor devicemay further be adapted to be an endoscope. In some implementations, thesensor device may be fabricated using existing wafer tools or PCB paneltool sets, as well as common glass handling and forming methodologies.In addition, off the shelf printed circuit assembly methods and partsmay be used.

FIGS. 1A-1B illustrate an embodiment of a sensor device according toaspects of the present disclosure. FIG. 1A illustrates a side view andFIG. 1B illustrates an end view of the exemplary sensor device. As shownin FIG. 1A, the sensor device includes a flexible PMUT array, a flexibleprinted circuit (PC) board, one or more integrated circuits (representedby Si Die), and a capsule. According to aspects of the presentdisclosure, different materials may be used for the capsule including,but not limited to, glass, ceramic, and titanium. In the end view of thesensor device, in addition to the flexible PMUT array, the flexible PCboard, the one or more integrated circuits, and the capsule, the sensordevice further includes a battery, and a coupling material. The batterymay be configured to provide power to the flexible PMUT array, and theone or more integrated circuits. The one or more integrated circuits mayinclude accelerated processing units (APUs), radio frequencycommunications components (RF COM), power management integrated circuits(PMIC), dynamic and static memories (MEM), gyroscopic sensor integratedcircuits (GYRO), other types of sensors, or other integrated circuits.The coupling material may be configured to hold the flexible PMUT array,the flexible PC board, the battery, and the one or more integratedcircuits in place with respect to the capsule. In some implementations,the battery may be charged wirelessly via ultrasonic waves or radiofrequency waves. The capsule may be configured to seal the flexible PMUTarray, the flexible PC board, the battery, the one or more integratedcircuits, and the coupling material within the capsule.

According to aspects of the present disclosure, the flexible PC board(also referred to as PC flex) may be bonded to flexible PMUT array (FPA)using anisotropic conductive film (ACF), solder paste, or other methods.If a surface mount battery is not used, connect leads of cylindricalbattery may be soldered to the flexible PC board. If surface mountbattery is used, flexible PC board and the FPA may be rolled around acylindrical holder (or battery), and the components may beclamped/tacked together into a coiled assembly. Inside of the capsulemay be coated with a thin layer of coupling material (such as polyimideor similar) and the coupling material may be partially cured (with UV orthermal). The coiled assembly may be inserted into the capsule (whichhas at least one end open) and then the coiled assembly may be releasedinside the capsule. Thereafter, the capsule may be filled with acoupling material or molding material and may be cured completely (forexample, using 150 degrees C. snap cure or UV safe for insert assembly).In addition, open end(s) of the capsule may be sealed (or molded) usingheat. Note that local heating may be controlled in such a way that theinserted assembly would not be damaged in the sealing step.

FIGS. 2A-2B illustrate another embodiment of a sensor device accordingto aspects of the present disclosure. FIG. 2A illustrates a side viewand FIG. 2B illustrates an end view of the exemplary sensor device. Inthe example shown in FIG. 2A the sensor device includes a flexible PMUTarray, a rigid printed circuit (PC) board, one or more integratedcircuits (represented by Si Die), and a capsule. In the end view of thesensor device shown in FIG. 2B, in addition to the flexible PMUT array,the rigid PC board, the one or more integrated circuits, and thecapsule, the sensor device further includes a battery, and a couplingmaterial. The battery may be configured to provide power to the flexiblePMUT array, and the one or more integrated circuits. The one or moreintegrated circuits may include APU, RF COM, PMIC, MEM, GYRO, etc. Thecoupling material may be configured to hold the flexible PMUT array, therigid PC board, the battery, and the one or more integrated circuits inplace with respect to the capsule. The capsule may be configured to sealthe flexible PMUT array, the rigid PC board, the battery, the one ormore integrated circuits, and the coupling material within the capsule.

FIGS. 3A-3B illustrate yet another embodiment of a sensor deviceaccording to aspects of the present disclosure. FIG. 3A illustrates aside view and FIG. 3B illustrates an end view of the exemplary sensordevice. In the example shown in FIG. 3A, the sensor device includes aflexible PMUT array, a flexible printed circuit (PC) board, one or moreintegrated circuits (represented by Si Die), a battery, and a capsule.In the end view of the sensor device shown in FIG. 3B, in addition tothe flexible PMUT array, the flexible PC board, the one or moreintegrated circuits, the battery and the capsule, the sensor devicefurther includes a coupling material. The battery may be configured toprovide power to the flexible PMUT array, and the one or more integratedcircuits. The one or more integrated circuits may include APU, RF COM,PMIC, MEM, GYRO, etc. The coupling material may be configured to holdthe flexible PMUT array, the flexible PC board, the battery, and the oneor more integrated circuits in place with respect to the capsule. Thecapsule may be configured to seal the flexible PMUT array, the flexiblePC board, the battery, the one or more integrated circuits, and thecoupling material within the capsule.

FIGS. 4A-4B illustrate yet another embodiment of a sensor deviceaccording to aspects of the present disclosure. FIG. 4A illustrates aside view and FIG. 4B illustrates an end view of the exemplary sensordevice. In the example shown in FIG. 4A, the sensor device includes aflexible PMUT array, a rigid-flexible printed circuit (PC) board (alsoreferred to as rigid-flex), one or more integrated circuits (representedby Si Die), a battery, and a capsule. In the end view of the sensordevice shown in FIG. 4B, in addition to the flexible PMUT array, therigid-flexible PC board, the one or more integrated circuits, thebattery and the capsule, the sensor device further includes a couplingmaterial. The battery may be configured to provide power to the flexiblePMUT array, and the one or more integrated circuits. The one or moreintegrated circuits may include APU, RF COM, PMIC, MEM, GYRO, etc. Thecoupling material may be configured to hold the flexible PMUT array, therigid-flexible PC board, the battery, and the one or more integratedcircuits in place with respect to the capsule. The capsule may beconfigured to seal the flexible PMUT array, the rigid-flexible PC board,the battery, the one or more integrated circuits, and the couplingmaterial within the capsule.

FIGS. 5A-5B illustrate yet another embodiment of a sensor deviceaccording to aspects of the present disclosure. FIG. 5A illustrates aside view and FIG. 5B illustrates an end view of the exemplary sensordevice. In the example shown in FIG. 5A, the sensor device includesmultiple rigid PMUT arrays, a rigid-flexible printed circuit (PC) board,one or more integrated circuits (represented by Si Die), a battery, anda capsule. In the end view of the sensor device shown in FIG. 5B, inaddition to the multiple rigid PMUT arrays, the rigid-flexible PC board,the one or more integrated circuits, the battery and the capsule, thesensor device further includes a coupling material. The battery may beconfigured to provide power to the multiple rigid PMUT arrays, and theone or more integrated circuits. The one or more integrated circuits mayinclude APU, RF COM, PMIC, MEM, GYRO, etc. The coupling material may beconfigured to hold the multiple rigid PMUT arrays, the rigid-flexible PCboard, the battery, and the one or more integrated circuits in placewith respect to the capsule. The capsule may be configured to seal themultiple rigid PMUT arrays, the rigid-flexible PC board, the battery,the one or more integrated circuits, and the coupling material withinthe capsule.

FIGS. 6A-6D illustrate exemplary implementations of coupling one or moreintegrated circuits to a PMUT array according to aspects of the presentdisclosure. FIG. 6A illustrates an example of integrating a flexiblePMUT array with multiple chip modules (also referred to as one or moreintegrated circuits, represented by Si Die and surface mounttransistor(s) SMT) on a flexible PC board. The flexible PMUT array maybe electrically connected to the flexible PC board using ACF. In someimplementations, other interconnect solutions, such as solder paste, maybe used.

FIG. 6B illustrates an example of integrating a flexible PMUT array withmultiple chip modules directly onto the backside of the flexible PMUT.The flexible PMUT array may be electrically connected to the multiplechip modules using various flexible interconnect solutions, such as ACF,solder paste, etc.

FIG. 6C illustrates an example of integrating a flexible PMUT array withmultiple chip modules directly onto the backside of the flexible PMUT.In this example, one or more chip modules may be implemented as thinsilicon (Thin Si). The flexible PMUT array may be electrically connectedto the thin silicon using various flexible interconnect solutions, suchas ACF, solder paste, etc.

FIG. 6D illustrates an example of integrating rigid PMUT arrays with oneor more integrated circuits (represented as Si Die and SMT) using arigid-flexible PC board. In this example, some sections of therigid-flexible PC board may be rigid, which may be used for attachingthe rigid PMUTs and Si Die. Some other sections of the rigid-flexible PCboard may be flexible, allowing the rigid-flexible PC board to bend andconform to a desired shape.

FIGS. 7A-7E illustrate exemplary embodiments of PMUT arrays according toaspects of the present disclosure. FIG. 7A illustrates an example of aPMUT 700 that can be replicated to form a flexible PMUT array. In thisexemplary implementation, the cavity 702 of the PMUT may be concealedwith different types of polymer materials (708 a and 708 b) on both thefront side and the back side of the PMUT 700. Vias (704 a and 704 b) andelectrodes (706 a and 706 b) may be provided to allow the PMUT 700 to beaccessed and controlled.

FIG. 7B illustrates an example of another PMUT 710 that may bereplicated to form a flexible PMUT array. In this exemplaryimplementation, the cavity 712 of the PMUT may be opened through anopening of a polymer material 718 b on the back side of the PMUT. Thefront side of the PMUT is covered with a polymer layer 718 a. Vias (714a and 714 b) and electrodes (716 a and 716 b) may be provided to allowthe PMUT 710 to be accessed and controlled.

FIG. 7C illustrates an example of yet another PMUT that may bereplicated to form a flexible PMUT array. In this exemplaryimplementation, the cavity 722 of the PMUT 720 may be concealed on boththe front side and the back side of the PMUT 720. In addition to polymerlayers (728 a and 728 b) covering the front side and the back side ofthe PMUT 720, a third polymer layer (728 c) may be deposited to coverthe polymer layer 728 a. Vias (724 a and 724 b) and electrodes (726 aand 726 b) may be provided to allow the PMUT 720 to be accessed andcontrolled.

FIG. 7D illustrates an example of yet another PMUT that may bereplicated to form a flexible PMUT array. In this exemplaryimplementation, the cavity 732 of the PMUT may be opened on the backside of the PMUT 730. In addition to polymer layers (738 a and 738 b)covering the front side and the back side of the PMUT 720 respectively,a third polymer layer (738 c) may be deposited on the front side of thePMUT 730. Vias (734 a and 734 b) and electrodes (736 a and 736 b) may beprovided to allow the PMUT 730 to be accessed and controlled.

FIG. 7E illustrates an example of yet another PMUT that may bereplicated to form a rigid PMUT array. In this exemplary implementation,the cavity 742 of the PMUT 740 may be concealed on both the front sideand the back side of the PMUT 740. The front side of the PMUT 740 iscovered with a polymer layer 748. A layer of rigid material 743, such asglass, may be attached to the back side of the PMUT. Vias (744 a and 744b) and electrodes (746 a and 746 b) may be provided to allow the PMUT740 to be accessed and controlled.

According to aspects of the present disclosure, the following tableprovides names, their corresponding definitions and exemplary materialsthat may be used for the various layers of a PMUT as described in FIGS.8A-8P and FIG. 9A-9M. The contents of the table show certain exemplaryimplementations. Different implementations, such as M1 may be used as anelectrode for signal while M2 may be used as an electrode for circuitground may be implemented. In addition, different materials may be usedto construct the different layers of the PMUT, in addition to thematerials shown in the table.

Layer Name Function/Definition Exemplary Material(s) SUB Rigid substrateGlass, Silicon CAR Carrier substrate Glass, Silicon, PCB core RELRelease layer for carrier UV release adhesive PL1 Base planarizationlayer Oxide (polished/plasma etched) PT Platten/mechanical Oxidemembrane ENC Encapsulation/passivation Oxide SEn Laminated polymer layerPhoto image-able polymer M1 Bottom electrode (Ground Moly plane) M2 Topelectrode (Signal) Moly/Aluminum M3 Routing/pads Aluminum (could beplated Cu) A2 Piezoelectric material Aluminum Nitride (200 deg. C.) V1Membrane release via Via to allow release of membrane cavity V2Electrode contact vias Contact vias for M1/M2 electrodes VP Pad vias Viato open passivation for contact to M3 S1 Cavity release layer a-Si (maybe Mo or polymer) E1 Encapsulation layer

FIGS. 8A-8P illustrate an exemplary implementation of forming a flexiblePMUT array for coupling to external logic according to aspects of thepresent disclosure. In this exemplary implementation, FIG. 8Aillustrates an example of coating a glass carrier (labeled as CAR) witha release film (labeled as REL). FIG. 8B illustrates an example ofpatterning redistribution layer (labeled as M0) metal and pads. FIG. 8Cillustrates an example of laminating a planarization polymer layer(labeled as SE1).

FIG. 8D illustrates an example of opening and filling contact vias tocreate pads (labeled as V0) at the top of the base polymer layer. FIG.8E illustrates an example of depositing a sacrificial material (labeledas S1), which may be patterned and etched to define a cavity of thePMUT. FIG. 8F illustrates an example of depositing an oxide layer(labeled as PL1) and performing planarization using chemical-mechanicalplanarization or etch-back.

FIG. 8G illustrates an example of depositing an oxide mechanical layer(labeled as PT). FIG. 8H illustrates an example of depositing apiezoelectric stack, including a bottom electrode (labeled as M1), apiezoelectric material (labeled as A2), and a top electrode (labeled asM2).

FIG. 8I illustrates an example of forming patterns on M1, M2, and A2.FIG. 8J illustrates an example of depositing a passivation layer(labeled as SE2) and opening release vias.

FIG. 8K illustrates an example of forming contact through etching. FIG.8L illustrates an example of forming a top redistribution layer.

FIG. 8M illustrates an example of etching a release via. FIG. 8Nillustrates an example of removing sacrificial material to form a cavitythrough etching.

FIG. 8O illustrates an example of forming an encapsulation (labeled asE1). FIG. 8P illustrates an example of forming the flexible PMUT byreleasing the carrier. The flexible PMUT array formed through thisprocess may be used to enable attachment of external logics from thebackside of the PMUT using pads and a redistribution layer for routing.

FIGS. 9A-9M illustrate another exemplary implementation of forming aflexible PMUT array for coupling to external logic according to aspectsof the present disclosure. In this exemplary implementation, FIG. 9Aillustrates an example of coating a glass carrier (labeled as CAR) witha release film (labeled as REL). FIG. 9B illustrates an example oflaminating planarization polymer layer (labeled as SE1). FIG. 9Cillustrates an example of depositing a piezoelectric stack, including abottom electrode (labeled as M1), a piezoelectric material (labeled asA2), and a top electrode (labeled as M2).

FIG. 9D illustrates an example of forming contact vias to access theelectrodes. FIG. 9E illustrates an example of depositing a mechanicallayer (labeled as PT). FIG. 9F illustrates an example of depositing asacrificial material (labeled as S1), which may be patterned and etchedto define a cavity of the PMUT.

FIG. 9G illustrates an example of laminating a second encapsulationlayer (labeled SE2) and opening initial vias for accessing theelectrodes. FIG. 9H illustrates an example of etching contact vias foraccessing the electrodes.

FIG. 9I illustrates an example of forming metal redistribution layers.FIG. 9J illustrates an example for opening release via.

FIG. 9K illustrates an example of removing sacrificial material to forma cavity through etching. FIG. 9L illustrates an example of forming anencapsulation layer (labeled as E1) and forming pad vias.

FIG. 9M illustrates an example of forming the flexible PMUT by releasingthe carrier. In this example, the PMUT formed from the steps of FIG. 9Ato FIG. 9L is turned upside down. The flexible PMUT array formed throughthis process may be used to enable attachment of external logics fromthe backside of the PMUT using pads and a redistribution layer forrouting.

FIGS. 10A-10E illustrate a method of manufacturing a sensor deviceaccording to aspects of the present disclosure. In FIG. 10A, on the lefthand side, a side view of a capsule 1002, a flexible PMUT array 1004,electronic components 1006, an inflatable device 1008, and a couplingmaterial 1010 of the sensor device are shown, respectively. On the righthand side, a cross sectional view of the capsule 1002, the flexible PMUTarray 1004, the electronic components 1006, the inflatable device 1008,and the coupling material 1010 of the sensor device are shown,respectively. Numeral 1012 may represent an air gap. The flexible PMUTarray 1004 and the electronic components 1006 may be attached to oneanother as described in FIG. 6A to FIG. 6D.

The flexible PMUT array 1004 and the electronic components 1006 may bewrapped around the inflatable device 1008 (also referred to as abladder). In one embodiment, the inflatable device 1008 may have acylindrical shape, with an opening at one end. The capsule 1002 may beconfigured to encapsulate the flexible PMUT array 1004 and theelectronic components 1006. FIG. 10A shows the view of the flexible PMUTarray 1004, the electronic components 1006, the inflatable device 1008,and other related components (not shown) prior to being inserted intothe capsule 1002. In some implementations, the other related componentsmay include, but not limited to, battery, flexible printed circuitboard, rigid-flexible printed circuit board, or some combinationsthereof. Each layer of the cross sectional view is described below inthe description of FIG. 10B.

In FIG. 10B, on the left hand side, a side view of the flexible PMUTarray 1004, the electronic components 1006, the inflatable device 1008,the coupling material 1010, and other related components after they arebeing inserted into the capsule 1002 is shown. In the middle, a crosssectional view of the flexible PMUT array 1004, the electroniccomponents 1006, the inflatable device 1008, the coupling material 1010,and other related components after they are being inserted into thecapsule 1002 is shown. On the right hand side, an enlarged crosssectional view is shown.

In some implementations, moving from inside to outside in the enlargedcross sectional view, the inner most layer may be the inflatable device1008; the next layer may be the flexible PMUT array 1004; the next layermay be the electronic components 1006; the next layer may be thecoupling material 1010 (also referred to as bonding material); the nextlayer may be an air gap 1012; and the outer most layer is the capsule1002. In some other implementations, the position of the flexible PMUTarray 1004 and the electronic components 1006 may be interchangeable.

In FIG. 10C, the inflatable device 1008 may be inflated to apredetermined pressure so that it is configured to push the flexiblePMUT array 1004, the electronic components 1006, and the couplingmaterial 1010 against the inner wall of the capsule 1002. On the lefthand side, a side view of the flexible PMUT array 1004, the electroniccomponents 1006, the inflatable device 1008, the coupling material 1010,and other related components after they are being pushed against theinner wall of the capsule 1002 is shown. On the right hand side, a crosssectional view of the flexible PMUT array 1004, the electroniccomponents 1006, the inflatable device 1008, the coupling material 1010,and other related components after they are being pushed against theinner wall of the capsule 1002 is shown.

Note that the air gap 1012 between the coupling material 1010 and theinner wall of the capsule 1002 may be substantially removed by theprocess of inflating the inflatable device 1008. The coupling material1010 may then be cured, for example by heat, UV light, or through othermeans. As a result of the curing process, the flexible PMUT array 1004,the electronic components 1006, and other related components may befirmly attached to the inner wall of the capsule 1002.

In FIG. 10D, the inflatable device 1008 may then be deflated. On theleft hand side, a side view of the inflatable device 1008 after it isbeing deflated is shown. On the right hand side, a cross sectional viewof the inflatable device 1008 after it is being deflated is shown. FIG.10E shows the side view and the cross sectional view of the sensordevice with the flexible PMUT array 1004, the electronic components1006, and other related components being attached to the inner wall ofthe capsule 1002 using the coupling material 1010. After the inflatabledevice 1008 has been removed, the capsule 1002 may then be sealed.

FIGS. 11A-11E illustrate a method of manufacturing a sensor deviceaccording to aspects of the present disclosure. In FIG. 11A, on the lefthand side, a side view of a capsule 1102, a flexible PMUT array 1104 andelectronic components 1106 a and 1106 b, an inflatable device 1108, anda coupling material 1110 of the sensor device are shown, respectively.On the right hand side, a cross sectional view of the capsule 1102, theflexible PMUT array 1104 and electronic components 1106 a and 1106 b,the inflatable device 1108, and the coupling material 1110 of the sensordevice are shown, respectively. Numeral 1112 may represent an air gap.The flexible PMUT array 1104 and the electronic components 1106 a and1106 b may be attached to one another as described in FIG. 6A to FIG.6D.

Note that the electronic components 1106 a and 1106 b may have differentphysical forms than those shown in FIG. 11A. Instead of having theelectronic components being wrapped around an inflatable device 1108(also referred to as a bladder), they may be held in the center of thesensor device in some implementations. Note that the connection betweenthe electronic components and the PMUT array is not shown in FIGS.11A-11E.

The inflatable device 1108 may have a sandwich shape to hold theelectronic components in the middle, with an opening at one end. Thecapsule 1102 may be configured to encapsulate the flexible PMUT array1104 and the electronic components 1006. FIG. 11A shows the view of theflexible PMUT array 1104, the electronic components 1106, the inflatabledevice 1108, and other related components (not shown) prior to beinginserted into the capsule 1102. According to aspects of the presentdisclosure, the other related components may include, but not limitedto, battery, flexible printed circuit board, rigid-flexible printedcircuit board, or some combinations thereof. The cross sectional view isfurther described below in association with the discussion of FIG. 11B.

In FIG. 11B, on the left hand side, a side view of the flexible PMUTarray 1104, the electronic components 1106, the inflatable device 1108,the coupling material 1110, and other related components after they arebeing inserted into the capsule 1102 is shown. In the middle, a crosssectional view of the flexible PMUT array 1104, the electroniccomponents 1106, the inflatable device 1108, the coupling material 1110,and other related components after they are being inserted into thecapsule 1102 is shown. On the right hand side, an enlarged crosssectional view is shown.

As shown in FIG. 11B, moving from inside to outside in the enlargedcross sectional view, the electronic components 1106 may be placed inthe middle of the capsule, which is then sandwiched by the inflatabledevice 1108; the next layer may be the flexible PMUT array 1104; thenext layer may be the coupling material 1110 (also referred to asbonding material); the next layer may be an air gap 1112; and the outermost layer is the capsule 1102.

In FIG. 11C, the inflatable device 1108 may be inflated to apredetermined pressure so that it is configured to push the flexiblePMUT array 1104, and the coupling material 1110 against the inner wallof the capsule 1102. On the left hand side, a side view of the flexiblePMUT array 1104, the electronic components 1106, the inflatable device1108, the coupling material 1110, and other related components afterthey are being pushed against the inner wall of the capsule 1102 isshown. On the right hand side, a cross sectional view of the flexiblePMUT array 1104, the electronic components 1106, the inflatable device1108, the coupling material 1110, and other related components afterthey are being pushed against the inner wall of the capsule 1102 isshown.

According to aspects of the present disclosure, the air gap 1112 betweenthe coupling material 1110 and the inner wall of the capsule 1102 may besubstantially removed by the process of inflating the inflatable device1108. The coupling material 1110 may then be cured, for example by heat,UV light, or through other means. As a result of the curing process, theflexible PMUT array 1104, the electronic components 1106, and otherrelated components can be firmly held in the capsule 1102.

In FIG. 11D, the inflatable device 1108 may then be deflated. On theleft hand side, a side view of the inflatable device 1108 after it isbeing deflated is shown. On the right hand side, a cross sectional viewof the inflatable device 1108 after it is being deflated is shown. FIG.11E shows the side view and the cross sectional view of the sensordevice with the flexible PMUT array 1104, the electronic components1106, and other related components being attached to the inner wall ofthe capsule 1102 using the coupling material 1110. After the inflatabledevice 1108 has been removed, the capsule 1102 may then be sealed.

According to aspects of the present disclosure, the sensor device asformed by using the methods and processes described from FIG. 1A-1B toFIG. 11A-11E may be employed in medical applications. For example, thesensor device may be configured in such a way that it may be swallowedby a patient, or it may be injected or implanted in a patient. Inaddition, the sensor device may be placed into a stent, catheter orother mechanical means for accessing and monitoring a patient. Thesensor device may hermetically sealed and may be made of glass, ceramic,titanium, or other materials that may minimize any reactions after beingingested, injected, or implanted in the body of the patent.

In an exemplary implementation, the sensor device as formed by using themethods and processes described from FIG. 1A-1B to FIG. 11A-11E may becompact and light weight. The physical characteristics of the sensordevice may have a height of 10.9 mm, a diameter of 2.6 mm, a weight of0.2 gram, and a volume of 0.06 cc. The electrical characteristics of thesensor device may have a nominal capacity of 1.5 mAh, a nominal voltageof 3.6V, a maximum recommended continuous discharge current of 1.5 mA,and an operating discharge temperature of 0° C. to 42° C. The sensordevice may be Zero-Volt™ enabled, hermetically sealed, and implantable.The sensor device may support biocompatibility and retains over 80% ofits original capacity at 500 cycles. It may further have lowself-discharge and long calendar life at elevated temperatures. In someother implementations, the capsule may be implemented in different sizesranging from 11.1 millimeter (mm) to 26.1 mm in length and 4.91 mm to9.91 mm in diameter.

According to aspects of the present disclosure, a method of forming anarray of piezoelectric micromechanical ultrasonic transducers (PMUTs)comprises, for each piezoelectric micromechanical ultrasonic transducer(PMUT) in the array of PMUTs: laminating a first polymer layerconfigured to support the PMUT, depositing a sacrificial materialconfigured to pattern a cavity of the PMUT, depositing a mechanicallayer configured to provide planarization to the PMUT, depositing afirst electrode configured to be coupled to a circuit ground plane,depositing a piezoelectric layer configured to separate the firstelectrode and a second electrode, depositing the second electrodeconfigured to be coupled to a signal, and creating patterns on the firstelectrode, the piezoelectric material, and the second electrodeconfigured to implement a design of the PMUT. Note that the mechanicallayer may include a planarization layer configured to provide chemicalmechanical planarization to the PMUT, a mechanical membrane configuredto provide stiffness to the PMUT, or some combination thereof.

In some implementations, the method may further include, prior tolaminating the first polymer layer, providing a carrier configured tosupport the PMUT, and providing a release layer configured to adherefirst polymer layer of the PMUT to the carrier. The method may yetfurther include depositing a passivation layer configured to encapsulatethe first electrode, the piezoelectric layer and the second electrode,etching contact vias configured to access the first electrode and thesecond electrode, and depositing pads and/or a redistribution layerconfigured to route electric signals to the first electrode and thesecond electrode.

Upon depositing the pads and/or redistribution layer configured to routeelectric signals to the first electrode and the second electrode, themethod may further include forming a cavity configured to adjust afrequency response of the PMUT, and removing the release layer toseparate the PMUT from the carrier. In an alternative implementation,the method may include forming a cavity configured to adjust a frequencyresponse of the PMUT, laminating an encapsulation polymer configured toprotect the PMUT, forming pattern vias configured to support signalaccess through the redistribution layer, and removing the release layerto separate the PMUT from the carrier. In another alternativeimplementation, the method may include laminating an encapsulationpolymer configured to protect the PMUT, forming pattern vias configuredto support signal access through the redistribution layer, removing therelease layer to separate the PMUT from the carrier, drilling a releasevia in the first polymer layer, and forming a cavity configured toadjust a frequency response of the PMUT by removing the sacrificialmaterial using the release via.

Upon providing a release layer configured to adhere first polymer layerof the PMUT to the carrier, the method may further include laminating apassivation polymer configured to encapsulate the first electrode, thepiezoelectric layer and the second electrode, patterning contact viasconfigured to access the first electrode and the second electrode, anddepositing pads and/or a redistribution layer configured to routeelectric signals to the first electrode and the second electrode. Next,in one exemplary implementation, the method may further include forminga cavity configured to adjust a frequency response of the PMUT, andremoving the release layer to separate the PMUT from the carrier. In analternative exemplary implementation, the method may include forming acavity configured to adjust a frequency response of the PMUT, laminatingan encapsulation polymer configured to protect the PMUT, forming patternvias configured to support signal access through the redistributionlayer, and removing the release layer to separate the PMUT from thecarrier. In yet another alternative exemplary implementation, the methodmay further include laminating an encapsulation polymer configured toprotect the PMUT, forming pattern vias configured to support signalaccess through the redistribution layer, removing the release layer toseparate the PMUT from the carrier, drilling a release via in the firstpolymer layer, and forming a cavity configured to adjust a frequencyresponse of the PMUT by removing the sacrificial material using therelease via.

The methodologies described herein may be implemented by various meansdepending upon applications according to particular examples. Forexample, such methodologies may be implemented in hardware, firmware,software, or combinations thereof. In a hardware implementation, forexample, a processing unit may be implemented within one or moreapplication specific integrated circuits (“ASICs”), digital signalprocessors (“DSPs”), digital signal processing devices (“DSPDs”),programmable logic devices (“PLDs”), field programmable gate arrays(“FPGAs”), processors, controllers, micro-controllers, microprocessors,electronic devices, other devices units designed to perform thefunctions described herein, or combinations thereof.

Some portions of the detailed description included herein are presentedin terms of algorithms or symbolic representations of operations onbinary digital signals stored within a memory of a specific apparatus orspecial purpose computing device or platform. In the context of thisparticular specification, the term specific apparatus or the likeincludes a general purpose computer once it is programmed to performparticular operations pursuant to instructions from program software.Algorithmic descriptions or symbolic representations are examples oftechniques used by those of ordinary skill in the signal processing orrelated arts to convey the substance of their work to others skilled inthe art. An algorithm is here, and generally, is considered to be aself-consistent sequence of operations or similar signal processingleading to a desired result. In this context, operations or processinginvolve physical manipulation of physical quantities. Typically,although not necessarily, such quantities may take the form ofelectrical or magnetic signals capable of being stored, transferred,combined, compared or otherwise manipulated. It has proven convenient attimes, principally for reasons of common usage, to refer to such signalsas bits, data, values, elements, symbols, characters, terms, numbers,numerals, or the like. It should be understood, however, that all ofthese or similar terms are to be associated with appropriate physicalquantities and are merely convenient labels. Unless specifically statedotherwise, as apparent from the discussion herein, it is appreciatedthat throughout this specification discussions utilizing terms such as“processing,” “computing,” “calculating,” “determining” or the likerefer to actions or processes of a specific apparatus, such as a specialpurpose computer, special purpose computing apparatus or a similarspecial purpose electronic computing device. In the context of thisspecification, therefore, a special purpose computer or a similarspecial purpose electronic computing device is capable of manipulatingor transforming signals, typically represented as physical electronic ormagnetic quantities within memories, registers, or other informationstorage devices, transmission devices, or display devices of the specialpurpose computer or similar special purpose electronic computing device.

Wireless communication techniques described herein may be in connectionwith various wireless communications networks such as a wireless widearea network (“WWAN”), a wireless local area network (“WLAN”), awireless personal area network (WPAN), and so on. The term “network” and“system” may be used interchangeably herein. A WWAN may be a CodeDivision Multiple Access (“CDMA”) network, a Time Division MultipleAccess (“TDMA”) network, a Frequency Division Multiple Access (“FDMA”)network, an Orthogonal Frequency Division Multiple Access (“OFDMA”)network, a Single-Carrier Frequency Division Multiple Access (“SC-FDMA”)network, or any combination of the above networks, and so on. A CDMAnetwork may implement one or more radio access technologies (“RATs”)such as cdma2000, Wideband-CDMA (“W-CDMA”), to name just a few radiotechnologies. Here, cdma2000 may include technologies implementedaccording to IS-95, IS-2000, and IS-856 standards. A TDMA network mayimplement Global System for Mobile Communications (“GSM”), DigitalAdvanced Mobile Phone System (“D-AMPS”), or some other RAT. GSM andW-CDMA are described in documents from a consortium named “3rdGeneration Partnership Project” (“3GPP”). Cdma2000 is described indocuments from a consortium named “3rd Generation Partnership Project 2”(“3GPP2”). 3GPP and 3GPP2 documents are publicly available. 4G Long TermEvolution (“LTE”) communications networks may also be implemented inaccordance with claimed subject matter, in an aspect. A WLAN maycomprise an IEEE 802.11x network, and a WPAN may comprise a Bluetooth®network, an IEEE 802.15x, for example. Wireless communicationimplementations described herein may also be used in connection with anycombination of WWAN, WLAN or WPAN.

In another aspect, as previously mentioned, a wireless transmitter oraccess point may comprise a femtocell, utilized to extend cellulartelephone service into a business or home. In such an implementation,one or more mobile devices may communicate with a femtocell via a codedivision multiple access (“CDMA”) cellular communication protocol, forexample, and the femtocell may provide the mobile device access to alarger cellular telecommunication network by way of another broadbandnetwork such as the Internet.

Techniques described herein may be used with a GPS that includes any oneof several GNSS and/or combinations of GNSS. Furthermore, suchtechniques may be used with positioning systems that utilize terrestrialtransmitters acting as “pseudolites”, or a combination of satellitevehicles (SVs) and such terrestrial transmitters. Terrestrialtransmitters may, for example, include ground-based transmitters thatbroadcast a PN code or other ranging code (e.g., similar to a GPS orCDMA cellular signal). Such a transmitter may be assigned a unique PNcode so as to permit identification by a remote receiver. Terrestrialtransmitters may be useful, for example, to augment a GPS in situationswhere GPS signals from an orbiting SV might be unavailable, such as intunnels, mines, buildings, urban canyons or other enclosed areas.Another implementation of pseudolites is known as radio-beacons. Theterm “SV”, as used herein, is intended to include terrestrialtransmitters acting as pseudolites, equivalents of pseudolites, andpossibly others. The terms “GPS signals” and/or “SV signals”, as usedherein, is intended to include GPS-like signals from terrestrialtransmitters, including terrestrial transmitters acting as pseudolitesor equivalents of pseudolites.

The terms, “and,” and “or” as used herein may include a variety ofmeanings that will depend at least in part upon the context in which itis used. Typically, “or” if used to associate a list, such as A, B or C,is intended to mean A, B, and C, here used in the inclusive sense, aswell as A, B or C, here used in the exclusive sense. Referencethroughout this specification to “one example” or “an example” meansthat a particular feature, structure, or characteristic described inconnection with the example is included in at least one example ofclaimed subject matter. Thus, the appearances of the phrase “in oneexample” or “an example” in various places throughout this specificationare not necessarily all referring to the same example. Furthermore, theparticular features, structures, or characteristics may be combined inone or more examples. Examples described herein may include machines,devices, engines, or apparatuses that operate using digital signals.Such signals may comprise electronic signals, optical signals,electromagnetic signals, or any form of energy that provides informationbetween locations.

While there has been illustrated and described what are presentlyconsidered to be example features, it will be understood by thoseskilled in the art that various other modifications may be made, andequivalents may be substituted, without departing from claimed subjectmatter. Additionally, many modifications may be made to adapt aparticular situation to the teachings of claimed subject matter withoutdeparting from the central concept described herein. Therefore, it isintended that claimed subject matter not be limited to the particularexamples disclosed, but that such claimed subject matter may alsoinclude all aspects falling within the scope of the appended claims, andequivalents thereof.

We claim:
 1. A sensor device, comprising: a piezoelectricmicromechanical ultrasonic transducer (PMUT) array configured totransmit and receive ultrasonic signals, wherein the PMUT arraycomprises a plurality of PMUTs, and the PMUT array is flexible; one ormore integrated circuits configured to process the ultrasonic signals; abattery configured to provide power to the PMUT array and the one ormore integrated circuits; a coupling material configured to hold thePMUT array, the one or more integrated circuits, and the battery; and acapsule configured to seal the PMUT array, the one or more integratedcircuits, the battery and the coupling material within the capsule. 2.The sensor device of claim 1, wherein each PMUT in the PMUT arraycomprises: a first polymer layer configured to support the PMUT; acavity configured to control a frequency response of the PMUT; amechanical layer configured to provide planarization to the PMUT; afirst electrode configured to be coupled to a circuit ground plane; asecond electrode configured to be coupled to a signal; and apiezoelectric layer configured to separate the first electrode and thesecond electrode.
 3. The sensor device of claim 2, wherein the cavity isoriented to face outwards from the capsule, wherein the cavity isconfigured to control the PMUT to operate in a first range of frequencyresponse.
 4. The sensor device of claim 2, wherein the cavity isoriented to face inwards from the capsule, wherein the cavity isconfigured to control the PMUT to operate in a second range of frequencyresponse.
 5. The sensor device of claim 2, wherein cavity is enclosed inone or more substrates of the PMUT, wherein the cavity encapsulates agaseous medium and is configured to control the PMUT to operate in athird range of frequency response.
 6. The sensor device of claim 1,further comprises: at least one of a flexible printed circuit board or arigid-flex printed circuit board configured to attach to the one or moreintegrated circuits; wherein the at least one of the flexible printedcircuit board or the rigid-flex printed circuit board is coupled to thePMUT array.
 7. The sensor device of claim 6, wherein the one or moreintegrated circuits are implemented on a thin silicon die, and whereinthe thin silicon die is coupled to the PMUT array.
 8. The sensor deviceof claim 6, wherein the PMUT array, the one or more integrated circuits,the battery and the coupling material are inserted into the capsule byan inflatable device.
 9. The sensor device of claim 8, wherein theinflatable device has a cylindrical shape, and wherein the PMUT array,the one or more integrated circuits, the battery and the couplingmaterial are wrapped around the inflatable device.
 10. The sensor deviceof claim 8, wherein the inflatable device has a U-shape; wherein thePMUT array and the coupling material are wrapped around the inflatabledevice, and the one or more integrated circuits and the battery aresandwiched by the inflatable device.
 11. The sensor device of claim 8,wherein the PMUT array, the one or more integrated circuits, the batteryand the coupling material are pushed against the inner wall of thecapsule by inflating the inflatable device.
 12. The sensor device ofclaim 11, wherein the coupling material is cured by heat or UV lightwhile the coupling material is being pushed against the inner wall ofthe capsule by the inflatable device.
 13. The sensor device of claim 12,wherein the inflatable device is deflated and removed from the capsuleafter the coupling material is cured, attaching the PMUT array, the oneor more integrated circuits, and the battery to the inner wall of thecapsule.
 14. The sensor device of claim 13, wherein the capsule issealed after the inflatable device is removed.
 15. The sensor device ofclaim 14, wherein the capsule is made of glass, ceramic, titanium, orsome combination thereof.
 16. A method of manufacturing a sensor device,comprising: providing a piezoelectric micromechanical ultrasonictransducer (PMUT) array configured to transmit and receive ultrasonicsignals, wherein the PMUT array comprises a plurality of PMUTs, and thePMUT array is flexible; providing one or more integrated circuitsconfigured to process the ultrasonic signals; providing a batteryconfigured to provide power to the PMUT array and the one or moreintegrated circuits; providing a coupling material configured to holdthe PMUT array, the one or more integrated circuits, and the battery;and providing a capsule configured to seal the PMUT array, the one ormore integrated circuits, the battery and the coupling material withinthe capsule.
 17. The method of claim 16, wherein each PMUT in the PMUTarray comprises: a first polymer layer configured to support the PMUT; acavity configured to control a frequency response of the PMUT; amechanical layer configured to provide planarization to the PMUT; afirst electrode configured to be coupled to a circuit ground plane; asecond electrode configured to be coupled to a signal; and apiezoelectric layer configured to separate the first electrode and thesecond electrode.
 18. The method of claim 17 further comprising:orienting the cavity to face outwards from the capsule, wherein thecavity is configured to control the PMUT to operate in a first range offrequency response.
 19. The method of claim 17 further comprising:orienting the cavity to face inwards from the capsule, wherein thecavity is configured to control the PMUT to operate in a second range offrequency response.
 20. The method of claim 17 further comprising:enclosing the cavity in one or more substrates of the PMUT, wherein thecavity encapsulates a gaseous medium and is configured to control thePMUT to operate in a third range of frequency response.
 21. The methodof claim 17, further comprising: attaching the one or more integratedcircuits to at least one of a flexible printed circuit board or arigid-flex printed circuit board; and attaching the at least one of theflexible printed circuit board or the rigid-flex printed circuit boardto the PMUT array.
 22. The method of claim 21, wherein the one or moreintegrated circuits are implemented on a thin silicon die, and whereinthe thin silicon die is coupled to the PMUT array.
 23. The method ofclaim 21 further comprising: inserting the PMUT array, the one or moreintegrated circuits, the battery and the coupling material into thecapsule by an inflatable device.
 24. The method of claim 23, wherein theinflatable device has a cylindrical shape, and wherein the PMUT array,the one or more integrated circuits, the battery and the couplingmaterial are wrapped around the inflatable device.
 25. The method ofclaim 23, wherein the inflatable device has a U-shape; wherein the PMUTarray and the coupling material are wrapped around the inflatabledevice, and the one or more integrated circuits and the battery aresandwiched by the inflatable device.
 26. The method of claim 23 furthercomprising: inflating the inflatable device to push the PMUT array, theone or more integrated circuits, the battery and the coupling materialagainst the inner wall of the capsule.
 27. The method of claim 26further comprising: curing the coupling material by heat or UV lightwhile the coupling material is being pushed against the inner wall ofthe capsule by the inflatable device.
 28. The method of claim 27,deflating the inflatable device after the coupling material is cured,attaching the PMUT array, the one or more integrated circuits, and thebattery to the inner wall of the capsule; and removing the inflatabledevice from the capsule.
 29. The method of claim 28 further comprising:sealing the capsule after the inflatable device is removed.
 30. Themethod of claim 29, wherein the capsule is made of glass, ceramic,titanium, or some combination thereof.